Activate the quads so that your legs work as a counter weight and focus on pulling you shoulders to your hips.
Try to keep your hands to your sides instead of under your back or butt. Legs should go from hovering to straight up.
Make sure to get a full rotation in and stomp the foot like as peadling a bike.
From a supine position, bring you foot up to your opposite hand. Try to keep your shoulders flat.